Mechanical advantage may be calculated using all of the following except

a. counting the number of supporting ropes of a pulley system

b. dividing resistance force by effort force

c. multiplying resistance force by effort force

d. dividing effort distance by resistance distance

The only exception of calculating mechanical advantage is by multiplying resistance force by effort force. For example, in calculating the mechanical advantage of a lever, we consider its output and input forces. The equation would now be as follows:

Mechanical advantage = output force / input force

Butterfly wingspan is 7.7